What is the primary energy source for sprouting plants?

2018-02-23 16:24:54

To what extent are young plants powered by the potential energy stored in the seeds and when does solar energy take over? Are there other energy sources involved?

I was observing sprouts in a germinator [is this a word?], pushing up the lid after being left alone over three-four days. As this is a considerable amount of work (for such young plants) I wondered how long the plant can access the original energy stored in the bean/seed and how it compares to the amount of energy it can get. As you can see in the picture, the sprouts have only access to water and some sunlight.

I suspect the potential energy it draws somehow decreases monotonically (perhaps linearly, quadratically, exponentially?) over time, while the solar energy pics up.

Is this mental model correct?

I'd appreciate an answer that a non-expert can understand.

I think these were radish sprouts, but my question is more general.